I think it depends on what you are seeking to learn or experience. I often suggest Brazilian jiujitsu because even if you don't stick with it, you can learn two interesting things - one, how to feel safe on the ground (even the basic siklls will give you this), and two, how to deal with panic and adrenal stress overload - and I can pretty much guarentee that you will feel these in a way you probably never have. It's interesting.